Multiple jet carburetor



Oct. 19, 1,937. l. T. swARTz ET AL MULTIPLE JET CARBURETOR 2 Sheets-Sheet.-l y

Original Filed March 20, 1933 Oct. 19, 1937. l. T.`swARTz ET AL 2,096,413

MULTIPLE JET CARBURETOR Original Filed March 20, 1935 2 Sheets-Sheet 2 i fra TSU/art Arf/mfg aler Patented Oct. 19, 1937 UNITED STATES PATENT OFFICE MULTIPLE JET CARBURETOR pany, Washington, D.

aware Application March 20,

C., a corporation of Del- 1933, Serial No. 661,817

Renewed January 7, 1936 10 Claims.

This invention relates to carburetors and its object is to provide a carburetor having a plurality of fuel jets and Venturi throats and also to provide automatically operable mechanism responsive to pressure conditions an-d to load and speed demands made upon the engine for controlling the fuel mixture supplied to the engine.

Many of the structural elements are similar to those shown in my patent No. 1,877,117, dated September 13, 1932. Other features are common to the copending application of Arthur R. Baker, Serial No. 661,809 filed of even date herewith for carburetor with choke control.

The carburetor of the present application by reason of the plurality of fuel nozzles is especially adaptedfor use with large displacement engines, particularly with engines which demand a larger supplyof motor fuel than may be ordinarily supi'plied by the usual carburetor having a single fuel jet and also in small displacement engines where automatic nozzle control is desirable due to altitude variations.

Referring to the accompanying drawings, which are made a part hereof and on which similarreference characters indicate similar parts,

Figure 1 is a plan view of a portion of the carburetor, j v

. Figure 2, a section on line 2 2 of Figure .1 with some elements omitted to avoid confusion, y AFigure 3, a section on line 3-3 of Figure 2,

Figure 4, a plan view similary to Figure 1 of a modifie-d form Ahaving two spray nozzles .and two barrels, and

Figure 5, a similar plan view having two spray nozzles delivering into a single hot cap and havling a single barrel or air intake.

Since the present application .is an improvement over the carburetor, shown in the patent and in the application referred to only so much of the structure will be lshown in the present application as is necessary to illustrate the improved features, reference being made to the above mentioned patent and application for further details of the common subject matter.

In Figure l two hot caps I and II extend into the exhaust chamber I2 from the internal comj bustion engine. The nozzles are alike in struc- Fuel is drawn through the annular passage 9 beture so itwill be necessary to describe but one. The hot cap I.I is shown broken away anda needle valve I3r is shown positioned vadjacent a valve vseat I4. Fuel is sprayed through the opening I4.

tween they needle Valve stem vI3 and the tube 8. vAir is drawn through lthe annular passage I between tube 8 and the tube 6 which extends into the hot cap. 'Ihe'needle valve I3 is adjustable toward and from the valve seat by a screw cap I5. The screw cap I5 is screw-threaded upon the Valve stem I3, rotation of the screw cap serving to move the valve stem toward and from its seat. The screw cap I5 is rotated by means of an arm I6 secured upon its outer end to which arm is attached a link I'I. This link at its outer end is secured to a diaphragm I8 positioned to close one side of a chamber i9. A spring acts against the inner side of the diaphragm to balance atmospheric pressure against the outer surface of the diaphragm. As will be apparent changes in atmospheric pressure will vary the pressure on the diaphragm. This pressure in turn is converted into rotary motion of the screw cap I5 to adjust the valve stem toward and from the valve seat. The purpose of this adjustment is to decrease the amount of fuel sprayed into the hot cap in proportion to a decrease in air pressure. At high elevations the pressure of the air is materially less than at sea level. A given volume of air at a high elevation therefore contains less oxygen than the same volume at sea level. The barometric control cuts off the supply of fuel in proportion to the decreased pressure of air which is equivalent to saying that the fuel is varied directly in proportion to the density of the air. I'he screw cap 2| controls a valve stem similar to I3 and this screw cap is manually operable by means of an arm 22 attached to the screw cap to which arm a link 23 is attached. The link 23 may be operated directly from the point of control of the engine, operation being either manual or otherwise. The mixture of air and motor fuel which has been heated in the hot caps IIJ and II passes through ports 24 and 25 into a bore 26 in a tube 21 which is threaded into the carburetor casing. This tube has an enlarged end having a conical surface Z8 against which air entering through the chamber 29 is deflected outwardly. An inwardly extending ridge 3B on a sleeve 34 cooperates with surface 28 to form a Venturi passage for air entering through chamber 29. Air passing through the throat formed between 28 and 39 aspirates the rich motor fuel passing through radial ports 3| and space 32 deliveringvit into the chamber 33 where it passes to the engine. The throttle opening between 28 and 39 is controlled by vertical movement of the sleeve 34. This sleeve may be manually operated in any suitable way such as by the mechanism shown in the patent or the application referred to. Means are provided as in the other application for supplying an additional volume vthe .Valve.38. into the tube being mixed with the air entering from outside the carburetor at 36.

means of a spring 45. The valve is tapered as shown at 4I so that the amount of fuel supplied is gradually increased as it is furtherdepressed by the sleeve 34. Means are providedfor'automatically choking the air to increase the supply of motor fuel in proportion'to air to start the engine. These consist of butterfly valves 42k and` 43 which are pivoted off center on shafts 44 and 53 respectively. Shaft 44 vcarries an arm having a pin 45 therein which pin engages normally against the side of a slotted arm 45 which arm is loosely mounted on the shaft 44. A link 4l is pivotally attached to the slottedA end of the arm 46 and this link 4l carries on its outer vend a piston and sealing cup 48 which cup is slidable in cylinder 49. The cylinder is closed by a cap 50 which is threaded into its open en-d and a light spring 5l surrounds the link'li'l having one end in engagement with the cap 5E! and the` other end engaging the inner side of the piston 48. The

end of the cylinder adjacent piston 48 is provided with an air port 52. An arm 54 is attached to shaft 53. Extending through 'the side of the carburetor casing is a fuel and air tube 55 similar to tube 35. Tube 55 is open to atmosphere through Va port 56. To the tube 55 there is connected a motor fuel port 5l which is normally closed by a valve 58 which is urged upon its seat by spring 59. `When the valve 58 is depressed fuel is allowed to flow through valve port 5".' into the tube 55 through which it is drawn into the suction chamber 29 where it is mixedvwith the air passing through the Venturi throat'. The Valve 58 is connected by means of a link 60 with thearm 54.

In operation fuel is supplied to the engine through either or both of the` nozzles through ports 24 and 25. This fuel is mixed with a relatively large volume of cold air coming in through the chamber 29. When the engine isffirst started,suction through the tube 29 will cause butterfly valve'43 to pivot on its shaft 53 counterclockwise.V The first result of this movement of the butterfly Valve will be to pulldownY the rvalve 5.8

Yand admit motor fluid through the valve port 51 Awhere it mixes with air coming through the tube 55 and the air which enters through openingat the butterfly valve 43. The addition of raw fuel into the air stream from fuel port 51 enriches the fuel mixture at the starting ofthe engine. Suction in the chamber 29 also causes the butter-v ily valve 42 to open, pivoting in a clockwise direc- Y tion. Movement of this valve is resisted by the vacuum created at the head of the cup washer The vacuum is slowly broken, however, by

` air which issues through the port 52.k Buttery valve 42 therefore willl open somewhat after butterfly valve 43 has opened. As soon as valve 42 is fully or even partially open valve 43 will close or tend to close under influence of spring. 59 which is of greater tension than spring 5l. The auxiliary fuel supply delivered to chamber 29 through tube 55 will therefore be cut off. .Valve K 42 will move to fully open position and will be :maintained in this position by the engine lsuction. The spring 5l will be only strong enough to restore 'the cup 48 to its original position after The valve 39 is urged against its seat byk the engine stops. The opening of thevalve 42 will be maintained in varying degree according to thev volumetric requirement of the enginey with a minimum of back pressure.

In the formshown in Figure 4 there are twoA hot caps 6I and 52 each having valves Aextending therein, which valves maybeoperate'd by screw caps G3 and '64 in the manner-'described in Fig.

ure l. A mixture o'fmotor Vfuel and air from the hot caps 5l and Y62 goeseach to its respec- Vtive air inlet barrel 55 and 65 and from these barrels fuel passes through openings' 61 and 53 into'the suctionrstreain of Ythe engine. In' this form the mixture of air and'motor fluid Vfollows f v two separatepathssoI as to form in eiect a double carburetor or double fuel supply for the engine.

The form-shown in--Figure 4 includes the valve Y assembly shown at the bottom of Figure 2.

vkIn the form shown in Figure 5fthe nozzles spray Y the fuel into a single hot cap 69 and from this fuel and air in relativelylarge lvolumes such as' are required for operation of ,largevehicles such as busses,rtrucks and the like. The form shown in Figure 5 includes also the Valve assembly shown Y at the. bottom of Figure V2. j Y

It will be obvious to those' skilled inthe art that various changes may be made in our device without departingfrom the spirit Iof the'invention and therefore we do not limit ourselves to what is shown in the ldrawings' and described in the specification, but only as-indicatedby the appended` claims. n A f L Having thus fully described .our said invention, what we claim .as new and ldesire to secure by Letters Patent, is; .Y s Y 1. In a carburetor havingA a plurality of h ot caps and a fuel spray nozzle extending into each of such hot caps, manually operable` means for adjusting someY of said spray nozzles,V and means .A

responsive toY changes in .atmospheric pressures for adjusting other spray nozzles'wherebygthe tially as set forth.- Y- Y' 2." Ina carburetor caps, a fuel nozzle deliveringintoreach ofsaid hot caps, manual means for adjusting one of saidfuel nozzles and means responsiveto varia--Y having .v a..pluralifsr7 of tion in air pressure for adjusting the other nozzle and a Venturi throttle for each of said hot caps forcontrolling passage of fuel from each of said hot caps to the engineysubstantially asset forth.`

3 1A carburetor having a'sin'glerhot cap posi? tioned in thejpathoffthe exhaust gases from-the engine,v a Vpair of. fuel spray nozzles'each posi-A tioned to direct fuel into. said hot capand for mixing itwithk air thereinjrandY a'l single Venturi throttle forY controlling the passage, of fuel. from said hot cap tol said engine, substantially'vas set forth. Y n I 4, In aA` carburetor Yfor an. internal combustion engine having an airintake for supplying air to Y f a fueimixture, a plurality or butterfly veuves positioned adjacent each other to close off said air intake said butterfly valves being pivoted 10 off center whereby passagel of air through said intake will tend toopen said-valves and `means operated by one of saidvalves for supplying-additional motorV fuelvto-said air supply at the start.

lof, the engine,substantiallyas'set forth. .Q,

5. In a carbureto-r having an air intake passage for supplying air to the fuel mixture, a pair of butterfly valves controlling said air intake passage, one of said butterfly valves operating to supply additional motive fluid to said air, the other butterfly valve being retarded in its action but opening under engine suction, opening of said last named butterfly valve permitting the first named butterfly Valve to close to cut off the additional supply of motor fuel to the air stream, substantially as set forth.

`6. In a carburetor of the kind described, means for making an initial fuel-air mixture,ymeans responsive to barometric changes for determining the richness of said mixture, means for making an additional fuel-air mixture, and means responsive to load, velocity and accelerating detures t0 the mixtures already made in response to vload velocity and accelerating demands for determining the quantity of the said second fuel air mixture.

8. In -a carburetor of the kind described, means for supplying a relatively large volume of fuel and air heated to a relatively high temperature,

a pair of butterfly valves for controlling the supply of scavenging air to said fuel mixture, one of said valves being in control of an additional fuel supply means and the other of said valves being responsive to load demands to throttle off the air at the beginning of speed acceleration and later opening to supply air in the correct proportions for normal operating speed and load.

9. In a carburetor of the kind described, means for supplying a relatively large volume of fuel and air heated to a relatively high temperature, means for supplying additional air to said rich hot body of fuel and air and means for supplying additional raw fuel to said additional air at the starting of the engine and for reducing the amount of said additional fuel as the engine comes to full speed.

10. Means for forming a fuel charge for an internal combustion engine comprising a chamber positioned in heat exchange relation with hot exhaust gases from the engine, means for supplying fuel and air to said chamber to be mixed and heated therein, means responsive to changes in atmospheric pressure for controlling the amount of fuel in proportion to air delivered to said chamber, means for supplying additional air to said mixture after the heating of the mixture and means for automatically supplying additional fuel at the moment of starting and increase of speed demands for fuel.

IRA T. SWARTZ. ARTHUR R. BAKER. 

